101
|
Li S, Miller CH, Giannopoulou E, Hu X, Ivashkiv LB, Zhao B. RBP-J imposes a requirement for ITAM-mediated costimulation of osteoclastogenesis. J Clin Invest 2014; 124:5057-73. [PMID: 25329696 PMCID: PMC4347236 DOI: 10.1172/jci71882] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/11/2014] [Indexed: 01/07/2023] Open
Abstract
Osteoclastogenesis requires activation of RANK signaling as well as costimulatory signals from immunoreceptor tyrosine-based activation motif-containing (ITAM-containing) receptors/adaptors, predominantly tyrosine kinase-binding proteins DAP12 and FcRγ, in osteoclast precursors. It is not well understood how costimulatory signals are regulated and integrated with RANK signaling. Here, we found that osteopetrotic bone phenotypes in mice lacking DAP12 or DAP12 and FcRγ are mediated by the transcription factor RBP-J, as deletion of Rbpj in these mice substantially rescued the defects of bone remodeling. Using a TNF-α-induced model of inflammatory bone resorption, we determined that RBP-J deficiency enables TNF-α to induce osteoclast formation and bone resorption in DAP12-deficient animals. Thus, RBP-J imposes a requirement for ITAM-mediated costimulation of RANKL or TNF-α-induced osteoclastogenesis. Mechanistically, RBP-J suppressed induction of key osteoclastogenic factors NFATc1, BLIMP1, and c-FOS by inhibiting ITAM-mediated expression and function of PLCγ2 and activation of downstream calcium-CaMKK/PYK2 signaling. Moreover, RBP-J suppressed Plcg2 expression and downstream calcium oscillations indirectly by a TGF-β/PLCγ2/calcium axis. Together, our findings indicate that RBP-J suppresses ITAM-mediated costimulation, thereby limiting crosstalk between ITAM and RANK/TNFR signaling and allowing fine tuning of osteoclastogenesis during bone homeostasis and under inflammatory conditions. Furthermore, these data suggest that environmental cues that regulate RBP-J expression/function potentially modulate the requirement for costimulatory signaling for osteoclast differentiation and bone remodeling.
Collapse
Affiliation(s)
- Susan Li
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Christine H. Miller
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Eugenia Giannopoulou
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Xiaoyu Hu
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Lionel B. Ivashkiv
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Baohong Zhao
- Arthritis and Tissue Degeneration Program and David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, USA. Biological Sciences Department, New York City College of Technology, City University of New York, New York, New York, USA. Department of Medicine and Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| |
Collapse
|
102
|
Pelham CJ, Pandya AN, Agrawal DK. Triggering receptor expressed on myeloid cells receptor family modulators: a patent review. Expert Opin Ther Pat 2014; 24:1383-95. [PMID: 25363248 DOI: 10.1517/13543776.2014.977865] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Triggering receptor expressed on myeloid cells (TREM) receptors and TREM-like transcript (TLT; or TREML) receptors of the immunoglobulin superfamily are known as key modulators of host immune responses. TREM-1 (CD354) and TREM-2 share the transmembrane adaptor DNAX-activation protein of 12 kDa (DAP12), but they possess separate stimulatory and inhibitory functional roles, especially in myeloid cells. AREAS COVERED This review covers findings related to TREMs and TLTs published in patent applications from their discovery in 2000 to the present. New roles for TREM-1, TREM-2, TLT-1 and TLT-2 in maladies ranging from acute and chronic inflammatory disorders to cardiovascular diseases and cancers are discussed. Putative endogenous ligands and novel synthetic peptide blockers are also discussed. EXPERT OPINION So far, therapeutic use of activators/blockers specific for TREMs and TLTs has been limited to preclinical animal models. TREM-1 is an immediate therapeutic target for acute and chronic inflammatory conditions, especially sepsis. Certain mutations in DAP12 and TREM-2 manifest into a disorder named polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, and newly identified TREM-2 variants confer a significant increase in risk of developing Alzheimer's disease. This makes TREM-2 an attractive therapeutic target for neurodegenerative diseases.
Collapse
Affiliation(s)
- Christopher J Pelham
- Creighton University School of Medicine, Department of Biomedical Sciences and Center for Clinical & Translational Science , Omaha, NE 68178 , USA
| | | | | |
Collapse
|
103
|
What happens to microglial TREM2 in Alzheimer's disease: Immunoregulatory turned into immunopathogenic? Neuroscience 2014; 302:138-50. [PMID: 25281879 DOI: 10.1016/j.neuroscience.2014.09.050] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/23/2014] [Accepted: 09/23/2014] [Indexed: 12/12/2022]
Abstract
Microglia play major roles in initiation, coordination and execution of innate immunity in the brain. In the adult brain, these include maintenance of homeostasis, neuron and tissue repair, and eliminating infectious agents, apoptotic cells, and misfolded proteins. Some of these activities are accompanied by inflammatory reactions; and others are performed with no inflammatory effects. Under normal conditions, triggering receptor expressed on myeloid cells 2 (TREM2) belongs to the second category. It pairs with the adaptor protein DNAX-activating protein of 12kDa (DAP12) to induce phagocytosis of apoptotic neurons without inflammatory responses, and to regulate Toll-like receptor-mediated inflammatory responses, and microglial activation. Although ligands for TREM2 are largely unknown, the mitochondrial heat shock protein 60, expressed on cell surface of apoptotic neurons, is a specific ligand that activates TREM2-mediated phagocytosis by microglia. TREM2 also phagocytoses amyloid beta peptide in cultured cells. Several TREM2 mutations have been identified recently that increase the risk of Alzheimer's disease, Frontotemporal dementia, Parkinson's disease, and amyotrophic lateral sclerosis. Some of these mutations cause impaired proteolysis of full-length TREM2 at the plasma membrane to different degrees. The defects in the intramembrane cleavage result in dysfunction of phagocytosis signaling. The association of TREM2 mutations with neurodegenerative disease also calls for the understanding of the biology and pathological role of non-mutated TREM2 on human brains and microglia. This review provides a summary of current literature in TREM2 and DAP12 from several aspects, and proposes a theory that loss of TREM2 functions might contribute to the immunopathogenic role of microglia in Alzheimer's disease.
Collapse
|
104
|
Albertsson AM, Bi D, Duan L, Zhang X, Leavenworth JW, Qiao L, Zhu C, Cardell S, Cantor H, Hagberg H, Mallard C, Wang X. The immune response after hypoxia-ischemia in a mouse model of preterm brain injury. J Neuroinflammation 2014; 11:153. [PMID: 25187205 PMCID: PMC4172879 DOI: 10.1186/s12974-014-0153-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/14/2014] [Indexed: 01/04/2023] Open
Abstract
Background Preterm brain injury consists primarily of periventricular leukomalacia accompanied by elements of gray-matter injury, and these injuries are associated with cerebral palsy and cognitive impairments. Inflammation is believed to be an important contributing factor to these injuries. The aim of this study was to examine the immune response in a postnatal day (PND) 5 mouse model of preterm brain injury induced by hypoxia-ischemia (HI) that is characterized by focal white and gray-matter injury. Methods C57Bl/6 mice at PND 5 were subjected to unilateral HI induced by left carotid artery ligation and subsequent exposure to 10% O2 for 50 minutes, 70 minutes, or 80 minutes. At seven days post-HI, the white/gray-matter injury was examined. The immune responses in the brain after HI were examined at different time points after HI using RT-PCR and immunohistochemical staining. Results HI for 70 minutes in PND 5 mice induced local white-matter injury with focal cortical injury and hippocampal atrophy, features that are similar to those seen in preterm brain injury in human infants. HI for 50 minutes resulted in a small percentage of animals being injured, and HI for 80 minutes produced extensive infarction in multiple brain areas. Various immune responses, including changes in transcription factors and cytokines that are associated with a T-helper (Th)1/Th17-type response, an increased number of CD4+ T-cells, and elevated levels of triggering receptor expressed on myeloid cells 2 (TREM-2) and its adaptor protein DNAX activation protein of 12 kDa (DAP12) were observed using the HI 70 minute preterm brain injury model. Conclusions We have established a reproducible model of HI in PND 5 mice that produces consistent local white/gray-matter brain damage that is relevant to preterm brain injury in human infants. This model provides a useful tool for studying preterm brain injury. Both innate and adaptive immune responses are observed after HI, and these show a strong pro-inflammatory Th1/Th17-type bias. Such findings provide a critical foundation for future studies on the mechanism of preterm brain injury and suggest that blocking the Th1/Th17-type immune response might provide neuroprotection after preterm brain injury.
Collapse
|
105
|
Totsuka N, Kim YG, Kanemaru K, Niizuma K, Umemoto E, Nagai K, Tahara-Hanaoka S, Nakahasi-Oda C, Honda SI, Miyasaka M, Shibuya K, Shibuya A. Toll-like receptor 4 and MAIR-II/CLM-4/LMIR2 immunoreceptor regulate VLA-4-mediated inflammatory monocyte migration. Nat Commun 2014; 5:4710. [PMID: 25134989 PMCID: PMC4143930 DOI: 10.1038/ncomms5710] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/15/2014] [Indexed: 12/24/2022] Open
Abstract
Inflammatory monocytes play an important role in host defense against infections. However, the regulatory mechanisms of transmigration into infected tissue are not yet completely understood. Here we show that mice deficient in MAIR-II (also called CLM-4 or LMIR2) are more susceptible to caecal ligation and puncture (CLP)-induced peritonitis than wild-type (WT) mice. Adoptive transfer of inflammatory monocytes from WT mice, but not from MAIR-II, TLR4 or MyD88-deficient mice, significantly improves survival of MAIR-II-deficient mice after CLP. Migration of inflammatory monocytes into the peritoneal cavity after CLP, which is dependent on VLA-4, is impaired in above mutant and FcRγ chain-deficient mice. Lipopolysaccharide stimulation induces association of MAIR-II with FcRγ chain and Syk, leading to enhancement of VLA-4-mediated adhesion to VCAM-1. These results indicate that activation of MAIR-II/FcRγ chain by TLR4/MyD88-mediated signalling is essential for the transmigration of inflammatory monocytes from the blood to sites of infection mediated by VLA-4. Inflammatory monocytes play an important role in host defense against infections. Here the authors provide insights into the mechanism behind the recruitment of inflammatory monocytes to sites of infection by demonstrating the involvement of Toll-like receptor 4 and MAIR-II immunoreceptors in this process.
Collapse
Affiliation(s)
- Naoya Totsuka
- 1] Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [2] Department of Immunology, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Fukushima 960-1295, Japan
| | - Yun-Gi Kim
- 1] Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [2] Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [3] Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, 1500 East Medical Center Dr-4111 CCGC, Ann Arbor, Michigan 48109, USA
| | - Kazumasa Kanemaru
- Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Kouta Niizuma
- Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Eiji Umemoto
- Laboratory of Immune Regulation, Department of Microbiology and Immunology, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kei Nagai
- Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Satoko Tahara-Hanaoka
- 1] Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [2] Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Chigusa Nakahasi-Oda
- Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Shin-ichiro Honda
- 1] Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [2] Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Masayuki Miyasaka
- Interdisciplinary Program for Biomedical Sciences, Institute for Academic Initiatives, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuko Shibuya
- Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Akira Shibuya
- 1] Department of Immunology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [2] Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan [3] Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| |
Collapse
|
106
|
Yoshida O, Kimura S, Dou L, Matta B, Yokota S, Stolz D, Geller D, Thomson AW. DAP12 deficiency in liver allografts results in enhanced donor DC migration, augmented effector T cell responses and abrogation of transplant tolerance. Am J Transplant 2014; 14:1791-805. [PMID: 24935196 PMCID: PMC4107008 DOI: 10.1111/ajt.12757] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/28/2014] [Accepted: 03/19/2014] [Indexed: 01/25/2023]
Abstract
Liver interstitial dendritic cells (DC) have been implicated in immune regulation and tolerance induction. We found that the transmembrane immuno-adaptor DNAX-activating protein of 12 kDa (DAP12) negatively regulated conventional liver myeloid (m) DC maturation and their in vivo migratory and T cell allostimulatory ability. Livers were transplanted from C57BL/6(H2(b) ) (B6) WT or DAP12(-/-) mice into WT C3H (H2(k) ) recipients. Donor mDC (H2-K(b+) CD11c(+) ) were quantified in spleens by flow cytometry. Anti-donor T cell reactivity was evaluated by ex vivo carboxyfluorescein diacetate succinimidyl ester-mixed leukocyte reaction and delayed-type hypersensitivity responses, while T effector and regulatory T cells were determined by flow analysis. A threefold to fourfold increase in donor-derived DC was detected in spleens of DAP12(-/-) liver recipients compared with those given WT grafts. Moreover, pro-inflammatory cytokine gene expression in the graft, interferon gamma (IFNγ) production by graft-infiltrating CD8(+) T cells and systemic levels of IFNγ were all elevated significantly in DAP12(-/-) liver recipients. DAP12(-/-) grafts also exhibited reduced incidences of CD4(+) Foxp3(+) cells and enhanced CD8(+) T cell IFNγ secretion in response to donor antigen challenge. Unlike WT grafts, DAP12(-/-) livers failed to induce tolerance and were rejected acutely. Thus, DAP12 expression in liver grafts regulates donor mDC migration to host lymphoid tissue, alloreactive T cell responses and transplant tolerance.
Collapse
Affiliation(s)
- O. Yoshida
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - S. Kimura
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - L. Dou
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Hepatic Surgery Center, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - B.M. Matta
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - S. Yokota
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - D.B. Stolz
- Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - D.A. Geller
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - A. W. Thomson
- Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh PA,Corresponding author: Angus W. Thomson PhD DSc Starzl Transplantation Institute University of Pittsburgh School of Medicine 200 Lothrop Street, W1540 BST Pittsburgh, PA 15261
| |
Collapse
|
107
|
Lo TH, Tseng KY, Tsao WS, Yang CY, Hsieh SL, Chiu AWH, Takai T, Mak TW, Tarng DC, Chen NJ. TREM-1 regulates macrophage polarization in ureteral obstruction. Kidney Int 2014; 86:1174-86. [PMID: 24918157 DOI: 10.1038/ki.2014.205] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 04/21/2014] [Accepted: 04/24/2014] [Indexed: 12/14/2022]
Abstract
Chronic kidney disease (CKD) is an emerging worldwide public health problem. Inflammatory cell infiltration and activation during the early stages in injured kidneys is a common pathologic feature of CKD. Here, we determined whether an important inflammatory regulator, triggering receptor expressed on myeloid cells (TREM)-1, is upregulated in renal tissues collected from mouse ureteral obstruction-induced nephritis. TREM-1 is crucial for modulating macrophage polarization, and has a pivotal role in mediating tubular injury and interstitial collagen deposition in obstructive nephritis. Lysates from nephritic kidneys triggered a TREM-1-dependent M1 polarization ex vivo, consistent with the observation that granulocyte-macrophage colony-stimulating factor (GM-CSF)-derived M1 macrophages express higher levels of TREM-1 in comparison with M-CSF-derived cells. Moreover, agonistic TREM-1 cross-link significantly strengthens the inductions of iNOS and GM-CSF in M1 cells. These observations are validated by a strong clinical correlation between infiltrating TREM-1-expressing/iNOS-positive macrophages and renal injury in human obstructive nephropathy. Thus, TREM-1 may be a potential diagnostic and therapeutic target in human kidney disease.
Collapse
Affiliation(s)
- Tzu-Han Lo
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan (ROC)
| | - Kai-Yu Tseng
- Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan (ROC)
| | - Wen-Shan Tsao
- Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan (ROC)
| | - Chih-Ya Yang
- 1] Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan (ROC) [2] Genomic Research Center, Academia Sinica, Taipei, Taiwan (ROC)
| | - Shie-Liang Hsieh
- 1] Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan (ROC) [2] Genomic Research Center, Academia Sinica, Taipei, Taiwan (ROC) [3] Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan (ROC) [4] Inflammation and Immunity Research Center, National Yang-Ming University, Taipei, Taiwan (ROC) [5] Immunology Center, Taipei Veterans General Hospital, Taipei, Taiwan (ROC) [6] Institute for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Allen Wen-Hsiang Chiu
- Department of Urology, School of Medicine, National Yang-Ming University, Taipei, Taiwan (ROC)
| | - Toshiyuki Takai
- Department of Experimental Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Tak W Mak
- The Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, University Health Network and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Der-Cherng Tarng
- 1] Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan (ROC) [2] Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan (ROC) [3] Inflammation and Immunity Research Center, National Yang-Ming University, Taipei, Taiwan (ROC) [4] Immunology Center, Taipei Veterans General Hospital, Taipei, Taiwan (ROC) [5] Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (ROC)
| | - Nien-Jung Chen
- 1] Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan (ROC) [2] Inflammation and Immunity Research Center, National Yang-Ming University, Taipei, Taiwan (ROC)
| |
Collapse
|
108
|
An ITAM-Syk-CARD9 signalling axis triggers contact hypersensitivity by stimulating IL-1 production in dendritic cells. Nat Commun 2014; 5:3755. [DOI: 10.1038/ncomms4755] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 03/28/2014] [Indexed: 12/14/2022] Open
|
109
|
Satoh JI, Motohashi N, Kino Y, Ishida T, Yagishita S, Jinnai K, Arai N, Nakamagoe K, Tamaoka A, Saito Y, Arima K. LC3, an autophagosome marker, is expressed on oligodendrocytes in Nasu-Hakola disease brains. Orphanet J Rare Dis 2014; 9:68. [PMID: 24886140 PMCID: PMC4022378 DOI: 10.1186/1750-1172-9-68] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/17/2014] [Indexed: 02/25/2023] Open
Abstract
Background Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder characterized by sclerosing leukoencephalopathy and multifocal bone cysts, caused by a loss-of-function mutation of either DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor signaling complex expressed exclusively on osteoclasts, dendritic cells, macrophages, and microglia. Neuropathologically, NHD exhibits profound loss of myelin and accumulation of axonal spheroids, accompanied by intense gliosis accentuated in the white matter of the frontal and temporal lobes. At present, the molecular mechanism responsible for development of leukoencephalopathy in NHD brains remains totally unknown. Methods By immunohistochemistry, we studied the expression of microtubule-associated protein 1 light chain 3 (LC3), an autophagosome marker, in 5 NHD and 12 control brains. Results In all NHD brains, Nogo-A-positive, CNPase-positive oligodendrocytes surviving in the non-demyelinated white matter intensely expressed LC3. They also expressed ubiquitin, ubiquilin-1, and histone deacetylase 6 (HDAC6) but did not express Beclin 1 or sequestosome 1 (p62). Substantial numbers of axonal spheroids were also labeled with LC3 in NHD brains. In contrast, none of oligodendrocytes expressed LC3 in control brains. Furthermore, surviving oligodendrocytes located at the demyelinated lesion edge of multiple sclerosis (MS) did not express LC3, whereas infiltrating Iba1-positive macrophages and microglia intensely expressed LC3 in MS lesions. Conclusions These results propose a novel hypothesis that aberrant regulation of autophagy might induce oligodendrogliopathy causative of leukoencephalopathy in NHD brains.
Collapse
Affiliation(s)
- Jun-Ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Tokyo, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
110
|
Montalvo V, Quigley L, Vistica BP, Boelte KC, Nugent LF, Takai T, McVicar DW, Gery I. Environmental factors determine DAP12 deficiency to either enhance or suppress immunopathogenic processes. Immunology 2014; 140:475-82. [PMID: 23906311 DOI: 10.1111/imm.12158] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/28/2013] [Accepted: 07/29/2013] [Indexed: 12/30/2022] Open
Abstract
DNAX-activation protein 12 (DAP12), a transmembrane adapter, plays a major role in transducing activation signals in natural killer cells and various myeloid cells. Quantitative RT-PCR detected in normal mouse eyes considerable levels of DAP12 and multiple DAP12-coupled receptors, in particular TREM-1, Clec5a and SIRPb1. The role of DAP12 and its receptors in experimental autoimmune diseases has been controversial. Here, we analysed the effect of DAP12 deficiency on the capacity of mice to mount immunopathogenic cellular responses to the uveitogenic ocular antigen and interphotoreceptor retinoid-binding protein (IRBP), and to develop experimental autoimmune uveitis (EAU). Surprisingly, sequential analysis of EAU in mice deficient in DAP12 in two different animal facilities at first revealed enhanced disease as compared with wild-type mice, but when these mice were re-derived into a second, cleaner, animal facility, the response of control mice was essentially unchanged, whereas the DAP12 null mice were markedly hyporesponsive relative to controls in the new facility. Accordingly, when stimulated in vitro with IRBP, lymphocytes from the DAP12-deficient mice housed in the two facilities proliferated and produced opposite profiles of pro-inflammatory and anti-inflammatory cytokines, compared with their controls. These findings therefore demonstrate that the effects of DAP12 deficiency on development of autoimmune disease are dramatically affected by environmental factors.
Collapse
Affiliation(s)
- Vanessa Montalvo
- Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD, USA
| | | | | | | | | | | | | | | |
Collapse
|
111
|
Xing J, Humphrey MB. Editorial: lipid kinases and bone homeostasis: lessons learned from phosphoinositide 3-kinase isoform-specific knockouts. Arthritis Rheumatol 2014; 66:1984-6. [PMID: 24719389 DOI: 10.1002/art.38661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 04/03/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Junjie Xing
- University of Oklahoma Health Sciences Center, Oklahoma City
| | | |
Collapse
|
112
|
Stuible M, Moraitis A, Fortin A, Saragosa S, Kalbakji A, Filion M, Tremblay GB. Mechanism and function of monoclonal antibodies targeting siglec-15 for therapeutic inhibition of osteoclastic bone resorption. J Biol Chem 2014; 289:6498-6512. [PMID: 24446437 DOI: 10.1074/jbc.m113.494542] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The use of monoclonal antibodies to target functionally important cell-surface proteins on bone-resorbing osteoclasts represents a promising approach for treatment of cancer-associated bone loss and other skeletal pathologies. Previously, we identified Siglec-15, a little studied sialic acid-binding receptor, as a candidate target that is highly up-regulated during osteoclast differentiation induced by the cytokine receptor activator of NF-κB ligand (RANKL). In this report, we confirm that Siglec-15 is localized to the plasma membrane where it can be targeted by monoclonal antibodies to inhibit differentiation of functional osteoclasts in vitro. Furthermore, we found that treatment of mice with these antibodies led to a marked increase in bone mineral density, consistent with inhibition of osteoclast activity. Interestingly, osteoblast numbers were maintained despite the anti-resorptive activity. At the molecular level, Siglec-15 interacts with the adapter protein DAP12 and can induce Akt activation when clustered on the osteoclast cell surface, which likely represents its normal signaling function. Importantly, we discovered that monoclonal antibodies induce rapid internalization, lysosomal targeting, and degradation of Siglec-15 by inducing receptor dimerization. This study defines a key regulatory node that controls osteoclast differentiation and activity downstream of RANKL and supports further development of Siglec-15 antibodies as a novel class of bone loss therapeutics.
Collapse
Affiliation(s)
- Matthew Stuible
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Anna Moraitis
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Annie Fortin
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Stefan Saragosa
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Aida Kalbakji
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Mario Filion
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada
| | - Gilles B Tremblay
- From Alethia Biotherapeutics Inc., Montréal, Québec H2X 1Y4, Canada.
| |
Collapse
|
113
|
Edmonson C, Ziats MN, Rennert OM. Altered glial marker expression in autistic post-mortem prefrontal cortex and cerebellum. Mol Autism 2014; 5:3. [PMID: 24410870 PMCID: PMC3914711 DOI: 10.1186/2040-2392-5-3] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 12/23/2013] [Indexed: 01/29/2023] Open
Abstract
Background The cellular mechanism(s) underlying autism spectrum disorders (ASDs) are not completely understood, but ASDs are thought to ultimately result from disrupted synaptogenesis. However, studies have also shown that glial cell numbers and function are abnormal in post-mortem brain tissue from autistic patients. Direct assessment of glial cells in post-mortem human brain tissue is technically challenging, limiting glial research in human ASD studies. Therefore, we attempted to determine if glial cell-type specific markers may be altered in autistic brain tissue in a manner that is consistent with known cellular findings, such that they could serve as a proxy for glial cell numbers and/or activation patterns. Methods We assessed the relative expression of five glial-specific markers and two neuron-specific markers via qRT-PCR. We studied tissue samples from the prefrontal cortex (PFC) and cerebellum of nine post-mortem autistic brain samples and nine neurologically-normal controls. Relative fold-change in gene expression was determined using the ΔΔCt method normalized to housekeeping gene β-actin, with a two-tailed Student’s t-test P <0.05 between groups considered as significant. Results Both astrocyte- and microglial-specific markers were significantly more highly expressed in autistic PFC as compared to matched controls, while in the cerebellum only astrocyte markers were elevated in autistic samples. In contrast, neuron-specific markers showed significantly lower expression in both the PFC and cerebellum of autistic patients as compared to controls. Conclusions These results are in line with previous findings showing increased glial cell numbers and up-regulation of glial cell gene expression in autistic post-mortem brain tissue, particularly in the PFC, as well as decreased number of neurons in both the PFC and cerebellum of autistic patients. The concordance of these results with cell-level studies in post-mortem autistic brain tissue suggests that expression of glial cell-type specific markers may serve as a useful alternative to traditional cellular characterization methods, especially when appropriately-preserved post-mortem tissue is lacking. Additionally, these results demonstrate abnormal glial-specific gene expression in autistic brains, supporting previous studies that have observed altered glial cell numbers or activation patterns in ASDs. Future work should directly assess the correlation between cell-type specific marker levels and cell number and activation patterns.
Collapse
Affiliation(s)
- Catherine Edmonson
- Laboratory of Clinical and Developmental Genomics, National Institute of Child Health and Human Development, National Institutes of Health, 49 Convent Drive, Building 49, Room 2C078, Bethesda, MD 20814, USA.,University of Florida College of Medicine, 1600 SW Archer Rd, Gainesville, FL 32603, USA
| | - Mark N Ziats
- Laboratory of Clinical and Developmental Genomics, National Institute of Child Health and Human Development, National Institutes of Health, 49 Convent Drive, Building 49, Room 2C078, Bethesda, MD 20814, USA.,University of Cambridge, Robinson College, Grange Rd, Cambridgeshire CB3 9AN, UK.,Baylor College of Medicine MSTP, One Baylor Plaza, Houston, TX 77030, USA
| | - Owen M Rennert
- Laboratory of Clinical and Developmental Genomics, National Institute of Child Health and Human Development, National Institutes of Health, 49 Convent Drive, Building 49, Room 2C078, Bethesda, MD 20814, USA
| |
Collapse
|
114
|
|
115
|
Role of TREM1-DAP12 in renal inflammation during obstructive nephropathy. PLoS One 2013; 8:e82498. [PMID: 24358193 PMCID: PMC3864959 DOI: 10.1371/journal.pone.0082498] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 10/24/2013] [Indexed: 01/05/2023] Open
Abstract
Tubulo-interstitial damage is a common finding in the chronically diseased kidney and is characterized by ongoing inflammation and fibrosis leading to renal dysfunction and end-stage renal disease. Upon kidney injury, endogenous ligands can be released which are recognized by innate immune sensors to alarm innate immune system. A new family of innate sensors is the family of TREM (triggering receptor expressed on myeloid cell). TREM1 is an activating receptor and requires association with transmembrane adapter molecule DAP12 (DNAX-associated protein 12) for cell signaling. TREM1-DAP12 pathway has a cross-talk with intracellular signaling pathways of several Toll-like receptors (TLRs) and is able to amplify TLR signaling and thereby contributes to the magnitude of inflammation. So far, several studies have shown that TLRs play a role in obstructive nephropathy but the contribution of TREM1-DAP12 herein is unknown. Therefore, we studied TREM1 expression in human and murine progressive renal diseases and further investigated the role for TREM1-DAP12 by subjecting wild-type (WT), TREM1/3 double KO and DAP12 KO mice to murine unilateral ureter obstruction (UUO) model. In patients with hydronephrosis, TREM1 positive cells were observed in renal tissue. We showed that in kidneys from WT mice, DAP12 mRNA and TREM1 mRNA and protein levels were elevated upon UUO. Compared to WT mice, DAP12 KO mice displayed less renal MCP-1, KC and TGF-β1 levels and less influx of macrophages during progression of UUO, whereas TREM1/3 double KO mice displayed less renal MCP-1 level. Renal fibrosis was comparable in WT, TREM1/3 double KO and DAP12 KO mice. We conclude that DAP12, partly through TREM1/3, is involved in renal inflammation during progression of UUO.
Collapse
|
116
|
Pelham CJ, Agrawal DK. Emerging roles for triggering receptor expressed on myeloid cells receptor family signaling in inflammatory diseases. Expert Rev Clin Immunol 2013; 10:243-56. [PMID: 24325404 DOI: 10.1586/1744666x.2014.866519] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Innate immune receptors represent important therapeutic targets for inflammatory disorders. In particular, the Toll-like receptor (TLR) family has emerged as a promoter of chronic inflammation that contributes to obesity, insulin resistance and atherosclerosis. Importantly, triggering receptor expressed on myeloid cells-1 (TREM-1) has been characterized as an 'amplifier' of TLR2 and TLR4 signaling. TREM-1- and TREM-2-dependent signaling, as opposed to TREM-like transcript-1 (TLT-1 or TREML1), are mediated through association with the transmembrane adaptor DNAX activation protein of 12 kDa (DAP12). Recessive inheritance of rare mutations in DAP12 or TREM-2 results in a disorder called polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, and surprisingly these subjects are not immunocompromised. Recent progress into the roles of TREM/DAP12 signaling is critically reviewed here with a focus on metabolic, cardiovascular and inflammatory diseases. The expanding repertoire of putative ligands for TREM receptors is also discussed.
Collapse
Affiliation(s)
- Christopher J Pelham
- Department of Biomedical Sciences and Center for Clinical & Translational Science, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA
| | | |
Collapse
|
117
|
Kameda Y, Takahata M, Komatsu M, Mikuni S, Hatakeyama S, Shimizu T, Angata T, Kinjo M, Minami A, Iwasaki N. Siglec-15 regulates osteoclast differentiation by modulating RANKL-induced phosphatidylinositol 3-kinase/Akt and Erk pathways in association with signaling Adaptor DAP12. J Bone Miner Res 2013; 28:2463-75. [PMID: 23677868 DOI: 10.1002/jbmr.1989] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 03/26/2013] [Accepted: 04/24/2013] [Indexed: 01/08/2023]
Abstract
Siglecs are a family of sialic acid-binding immunoglobulin-like lectins that regulate the functions of cells in the innate and adaptive immune systems through glycan recognition. Here we show that Siglec-15 regulates osteoclast development and bone resorption by modulating receptor activator of nuclear factor κB ligand (RANKL) signaling in association with DNAX-activating protein 12 kDa (DAP12), an adaptor protein bearing an immunoreceptor tyrosine-based activation motif (ITAM). Among the known Siglecs expressed in myeloid lineage cells, only Siglec-15 was upregulated by RANKL in mouse primary bone marrow macrophages. Siglec-15-deficient mice exhibit mild osteopetrosis resulting from impaired osteoclast development. Consistently, cells lacking Siglec-15 exhibit defective osteoclast development and resorptive activity in vitro. RANKL-induced activation of phosphatidylinositol 3-kinase (PI3K)/Akt and Erk pathways were impaired in Siglec-15-deficient cells. Retroviral transduction of Siglec-15-null osteoclast precursors with wild-type Siglec-15 or mutant Siglec-15 revealed that the association of Siglec-15 with DAP12 is involved in the downstream signal transduction of RANK. Furthermore, we found that the ability of osteoclast formation is preserved in the region adjacent to the growth plate in Siglec-15-deficient mice, indicating that there is a compensatory mechanism for Siglec-15-mediated osteoclastogenesis in the primary spongiosa. To clarify the mechanism of this compensation, we examined whether osteoclast-associated receptor (OSCAR)/Fc receptor common γ (FcRγ) signaling, an alternative ITAM-mediated signaling pathway to DAP12, rescues impaired osteoclastogenesis in Siglec-15-deficient cells. The ligands in type II collagen activate OSCAR and rescue impaired osteoclastogenesis in Siglec-15-deficient cells when cultured on bone slices, indicating that Siglec-15-mediated signaling can be compensated for by signaling activated by type II collagen and other bone matrix components in the primary spongiosa. Our findings indicate that Siglec-15 plays an important role in physiologic bone remodeling by modulating RANKL signaling, especially in the secondary spongiosa.
Collapse
Affiliation(s)
- Yusuke Kameda
- Department of Orthopedic Surgery, School of Medicine, Hokkaido University, Sapporo, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
118
|
Microglial beclin 1 regulates retromer trafficking and phagocytosis and is impaired in Alzheimer's disease. Neuron 2013; 79:873-86. [PMID: 24012002 DOI: 10.1016/j.neuron.2013.06.046] [Citation(s) in RCA: 285] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2013] [Indexed: 01/13/2023]
Abstract
Phagocytosis controls CNS homeostasis by facilitating the removal of unwanted cellular debris. Accordingly, impairments in different receptors or proteins involved in phagocytosis result in enhanced inflammation and neurodegeneration. While various studies have identified extrinsic factors that modulate phagocytosis in health and disease, key intracellular regulators are less understood. Here we show that the autophagy protein beclin 1 is required for efficient phagocytosis in vitro and in mouse brains. Furthermore, we show that beclin 1-mediated impairments in phagocytosis are associated with dysfunctional recruitment of retromer to phagosomal membranes, reduced retromer levels, and impaired recycling of phagocytic receptors CD36 and Trem2. Interestingly, microglia isolated from human Alzheimer's disease (AD) brains show significantly reduced beclin 1 and retromer protein levels. These findings position beclin 1 as a link between autophagy, retromer trafficking, and receptor-mediated phagocytosis and provide insight into mechanisms by which phagocytosis is regulated and how it may become impaired in AD.
Collapse
|
119
|
Chertoff M, Shrivastava K, Gonzalez B, Acarin L, Giménez-Llort L. Differential modulation of TREM2 protein during postnatal brain development in mice. PLoS One 2013; 8:e72083. [PMID: 23977213 PMCID: PMC3747061 DOI: 10.1371/journal.pone.0072083] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/04/2013] [Indexed: 01/25/2023] Open
Abstract
During postnatal development, microglia, the resident innate immune cells of the central nervous system are constantly monitoring the brain parenchyma, cleaning the cell debris, the synaptic contacts overproduced and also maintaining the brain homeostasis. In this context, the postnatal microglia need some control over the innate immune response. One such molecule recently described to be involved in modulation of immune response is TREM2 (triggering receptor expressed on myeloid cells 2). Although some studies have observed TREM2 mRNA in postnatal brain, the regional pattern of the TREM2 protein has not been described. We therefore characterized the distribution of TREM2 protein in mice brain from Postnatal day (P) 1 to 14 by immunostaining. In our study, TREM2 protein was expressed only in microglia/macrophages and is developmentally downregulated in a region-dependent manner. Its expression persisted in white matter, mainly in caudal corpus callosum, and the neurogenic subventricular zone for a longer time than in grey matter. Additionally, the phenotypes of the TREM2+ microglia also differ; expressing CD16/32, MHCII and CD86 (antigen presentation markers) and CD68 (phagocytic marker) in different regions as well as with different intensity till P7. The mannose receptor (CD206) colocalized with TREM2 only at P1–P3 in the subventricular zone and cingulum, while others persisted at low intensities till P7. Furthermore, the spatiotemporal expression pattern and characterization of TREM2 indicate towards its other plausible roles in phagocytosis, progenitor’s fate determination or microglia phenotype modulation during postnatal development. Hence, the increase of TREM2 observed in pathologies may recapitulate their function during postnatal development, as a better understanding of this period may open new pathway for future therapies.
Collapse
Affiliation(s)
- Mariela Chertoff
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat Autonoma Barcelona, Barcelona, Spain
- * E-mail:
| | - Kalpana Shrivastava
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Berta Gonzalez
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Laia Acarin
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Lydia Giménez-Llort
- Department of Psychiatry and Forensic Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat Autonoma Barcelona, Barcelona, Spain
| |
Collapse
|
120
|
Breast cancer expression of DAP12 is associated with skeletal and liver metastases and poor survival. Clin Breast Cancer 2013; 13:371-7. [PMID: 23810293 DOI: 10.1016/j.clbc.2013.05.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 04/30/2013] [Accepted: 05/03/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND The transmembrane adapter protein, DAP12, transduces activation signals for several arrays of receptors, including human signal-regulatory protein, DAP12-associating lectin-1, triggering receptor expressed on myeloid cells-1, -2, and -3, in natural killer cells, granulocytes, monocytes/macrophages, and dendritic cells. The macrophage-specific antigen, Cluster of Differentiation 163 (CD163), is expressed in breast and colorectal cancers and is associated with early cancer recurrence and poor prognosis. It was recently shown that fusion between intestinal tumor cells and macrophages results in nuclear reprogramming with hybrid transcripts from both cells of origin. The role of DAP12 in the fusion process is not known. This study investigates the expression of DAP12 in BRC cells, and its relation to other macrophage traits and to the clinical progression of disease. MATERIALS AND METHODS Immunostaining of DAP12 and CD163 was performed and evaluated in paraffin-embedded specimens from 132 patients with BRC. The outcomes were analyzed in relation to clinicopathological data. RESULTS DAP12 expression in cancer cells was positive in 66 percent of the cancers and was associated with high tumor grade (P = .015), and with liver (P = .047) and skeletal (P = .067), but not with lung metastases (P = 1.00). Patients with BRC expressing DAP12 had poor prognosis, with higher recurrence rates of skeletal (P = .018) and liver metastases (P = .047), and shorter survival time (P = .0060). CONCLUSION We suggest that macrophage traits in BRC cells facilitate the metastatic process and that DAP12 expression might promote metastatic homing to bone and liver tissues.
Collapse
|
121
|
DAP12 overexpression induces osteopenia and impaired early hematopoiesis. PLoS One 2013; 8:e65297. [PMID: 23776468 PMCID: PMC3679081 DOI: 10.1371/journal.pone.0065297] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 04/28/2013] [Indexed: 01/25/2023] Open
Abstract
ITAM-bearing transmembrane signaling adaptors such as DAP12 and FcRγ are important players in bone homeostasis, but their precise role and functions are still unknown. It has been shown that osteoclast differentiation results from the integration of the RANK and of the DAP12 and FcRγ signaling pathways. DAP12-deficient mice suffer from a mild osteopetrosis and culture of their bone marrow cells in the presence of M-CSF and RANKL, fails to give rise to multinucleated osteoclasts. Here, we report that mice overexpressing human DAP12 have an osteopenic bone phenotype due to an increased number of osteoclasts on the surface of trabecular and cortical bone. This enhanced number of osteoclasts is associated with an increased number of proliferating myeloid progenitors in Tg-hDAP12 mice. It is concomitant with an arrest of B cell development at the Pre-Pro B/Pre B stage in the bone marrow of Tg-hDAP12 mice and important decrease of follicular and marginal B cells in the spleen of these animals. Our data show that the overexpression of DAP12 results in both increased osteoclastogenesis and impaired hematopoiesis underlining the relationship between bone homeostasis and hematopoiesis.
Collapse
|
122
|
Paradowska-Gorycka A, Jurkowska M. Structure, expression pattern and biological activity of molecular complex TREM-2/DAP12. Hum Immunol 2013; 74:730-7. [DOI: 10.1016/j.humimm.2013.02.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 01/24/2013] [Accepted: 02/19/2013] [Indexed: 01/05/2023]
|
123
|
Béchade C, Cantaut-Belarif Y, Bessis A. Microglial control of neuronal activity. Front Cell Neurosci 2013; 7:32. [PMID: 23543873 PMCID: PMC3610058 DOI: 10.3389/fncel.2013.00032] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/13/2013] [Indexed: 01/27/2023] Open
Abstract
Fine-tuning of neuronal activity was thought to be a neuron-autonomous mechanism until the discovery that astrocytes are active players of synaptic transmission. The involvement of astrocytes has changed our understanding of the roles of non-neuronal cells and shed new light on the regulation of neuronal activity. Microglial cells are the macrophages of the brain and they have been mostly investigated as immune cells. However, recent data discussed in this review support the notion that, similarly to astrocytes, microglia are involved in the regulation of neuronal activity. For instance, in most, if not all, brain pathologies a strong temporal correlation has long been known to exist between the pathological activation of microglia and dysfunction of neuronal activity. Recent studies have convincingly shown that alteration of microglial function is responsible for pathological neuronal activity. This causal relationship has also been demonstrated in mice bearing loss-of-function mutations in genes specifically expressed by microglia. In addition to these long-term regulations of neuronal activity, recent data show that microglia can also rapidly regulate neuronal activity, thereby acting as partners of neurotransmission.
Collapse
Affiliation(s)
- Catherine Béchade
- Institut de Biologie, Ecole Normale Supérieure, Inserm U1025, CNRS UMR8197 Paris, France
| | | | | |
Collapse
|
124
|
Early estrogen-induced gene 1, a novel RANK signaling component, is essential for osteoclastogenesis. Cell Res 2013; 23:524-36. [PMID: 23478294 DOI: 10.1038/cr.2013.33] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The receptor activator of NF-κB (RANK) and immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors are essential factors involved in regulating osteoclast formation and bone remodeling. Here, we identify early estrogen-induced gene 1 (EEIG1) as a novel RANK ligand (RANKL)-inducible protein that physically interacts with RANK and further associates with Gab2, PLCγ2 and Tec/Btk kinases upon RANKL stimulation. EEIG1 positively regulates RANKL-induced osteoclast formation, likely due to its ability to facilitate RANKL-stimulated PLCγ2 phosphorylation and NFATc1 induction. In addition, an inhibitory peptide designed to block RANK-EEIG1 interaction inhibited RANKL-induced bone destruction by reducing osteoclast formation. Together, our results identify EEIG1 as a novel RANK signaling component controlling RANK-mediated osteoclast formation, and suggest that targeting EEIG1 might represent a new therapeutic strategy for the treatment of pathological bone resorption.
Collapse
|
125
|
Hiruma Y, Tsuda E, Maeda N, Okada A, Kabasawa N, Miyamoto M, Hattori H, Fukuda C. Impaired osteoclast differentiation and function and mild osteopetrosis development in Siglec-15-deficient mice. Bone 2013; 53:87-93. [PMID: 23238125 DOI: 10.1016/j.bone.2012.11.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/12/2012] [Accepted: 11/17/2012] [Indexed: 12/20/2022]
Abstract
Sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) is a cell surface receptor for sialylated glycan ligands. Recent in vitro studies revealed upregulated Siglec-15 expression in differentiated osteoclasts and inhibition of osteoclast differentiation by anti-Siglec-15 polyclonal antibody, demonstrating Siglec-15 involvement in osteoclastogenesis. To discern the physiological role of Siglec-15 in skeletal development and osteoclast formation and/or function in vivo, we generated Siglec-15-deficient (siglec-15(-/-)) mice and analyzed their phenotype. The siglec-15(-/-) mice developed without physical abnormalities other than increased trabecular bone mass in lumbar vertebrae and metaphyseal regions of the femur and tibia, causing mild osteopetrosis. Histological analyses demonstrated that the number of osteoclasts present on the femoral trabecular bone of the mutant mice was comparable to that of the wild-type mice. However, urinary deoxypyridinoline, a systemic bone resorption marker, decreased in the siglec-15(-/-) mice, indicating that impaired osteoclast function was responsible for increased bone mass in the mutant mice. In addition, the ability of bone marrow-derived monocytes/macrophages from the siglec-15(-/-) mice to differentiate into osteoclasts was impaired, as determined in vitro by cellular tartrate-resistant acid phosphatase activity in response to the receptor activator of nuclear factor-κB ligand or tumor necrosis factor-α. These results reveal the importance of Siglec-15 in the regulation of osteoclast formation and/or function in vivo, providing new insights into osteoclast biology.
Collapse
Affiliation(s)
- Yoshiharu Hiruma
- Frontier Research Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
126
|
Polycystic Lipomembranous Osteodysplasia with Sclerosing Leukoencephalopathy (PLOSL): A new report of an Italian woman and review of the literature. J Neurol Sci 2013; 326:115-9. [DOI: 10.1016/j.jns.2013.01.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 01/13/2013] [Accepted: 01/15/2013] [Indexed: 11/22/2022]
|
127
|
Sierra A, Abiega O, Shahraz A, Neumann H. Janus-faced microglia: beneficial and detrimental consequences of microglial phagocytosis. Front Cell Neurosci 2013. [PMID: 23386811 DOI: 10.3389/fncel.2013.00006/abstract] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and microbes. In addition, microglia phagocytoses brain-specific cargo, such as axonal and myelin debris in spinal cord injury or multiple sclerosis, amyloid-β deposits in Alzheimer's disease, and supernumerary synapses in postnatal development. Common mechanisms of recognition, engulfment, and degradation of the different types of cargo are assumed, but very little is known about the shared and specific molecules involved in the phagocytosis of each target by microglia. More importantly, the functional consequences of microglial phagocytosis remain largely unexplored. Overall, phagocytosis is considered a beneficial phenomenon, since it eliminates dead cells and induces an anti-inflammatory response. However, phagocytosis can also activate the respiratory burst, which produces toxic reactive oxygen species (ROS). Phagocytosis has been traditionally studied in pathological conditions, leading to the assumption that microglia have to be activated in order to become efficient phagocytes. Recent data, however, has shown that unchallenged microglia phagocytose apoptotic cells during development and in adult neurogenic niches, suggesting an overlooked role in brain remodeling throughout the normal lifespan. The present review will summarize the current state of the literature regarding the role of microglial phagocytosis in maintaining tissue homeostasis in health as in disease.
Collapse
Affiliation(s)
- Amanda Sierra
- Achucarro-Basque Center for Neuroscience Zamudio, Spain ; Department of Neuroscience, University of the Basque Country EHU/UPV Leioa, Spain ; Ikerbasque-Basque Foundation for Science Bilbao, Spain
| | | | | | | |
Collapse
|
128
|
Sierra A, Abiega O, Shahraz A, Neumann H. Janus-faced microglia: beneficial and detrimental consequences of microglial phagocytosis. Front Cell Neurosci 2013; 7:6. [PMID: 23386811 PMCID: PMC3558702 DOI: 10.3389/fncel.2013.00006] [Citation(s) in RCA: 394] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/09/2013] [Indexed: 02/04/2023] Open
Abstract
Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and microbes. In addition, microglia phagocytoses brain-specific cargo, such as axonal and myelin debris in spinal cord injury or multiple sclerosis, amyloid-β deposits in Alzheimer's disease, and supernumerary synapses in postnatal development. Common mechanisms of recognition, engulfment, and degradation of the different types of cargo are assumed, but very little is known about the shared and specific molecules involved in the phagocytosis of each target by microglia. More importantly, the functional consequences of microglial phagocytosis remain largely unexplored. Overall, phagocytosis is considered a beneficial phenomenon, since it eliminates dead cells and induces an anti-inflammatory response. However, phagocytosis can also activate the respiratory burst, which produces toxic reactive oxygen species (ROS). Phagocytosis has been traditionally studied in pathological conditions, leading to the assumption that microglia have to be activated in order to become efficient phagocytes. Recent data, however, has shown that unchallenged microglia phagocytose apoptotic cells during development and in adult neurogenic niches, suggesting an overlooked role in brain remodeling throughout the normal lifespan. The present review will summarize the current state of the literature regarding the role of microglial phagocytosis in maintaining tissue homeostasis in health as in disease.
Collapse
Affiliation(s)
- Amanda Sierra
- Achucarro-Basque Center for Neuroscience Zamudio, Spain ; Department of Neuroscience, University of the Basque Country EHU/UPV Leioa, Spain ; Ikerbasque-Basque Foundation for Science Bilbao, Spain
| | | | | | | |
Collapse
|
129
|
Xu J, Sun J, Chen J, Wang L, Li A, Helm M, Dubovsky SL, Bacanu SA, Zhao Z, Chen X. RNA-Seq analysis implicates dysregulation of the immune system in schizophrenia. BMC Genomics 2012; 13 Suppl 8:S2. [PMID: 23282246 PMCID: PMC3535722 DOI: 10.1186/1471-2164-13-s8-s2] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND While genome-wide association studies identified some promising candidates for schizophrenia, the majority of risk genes remained unknown. We were interested in testing whether integration gene expression and other functional information could facilitate the identification of susceptibility genes and related biological pathways. RESULTS We conducted high throughput sequencing analyses to evaluate mRNA expression in blood samples isolated from 3 schizophrenia patients and 3 healthy controls. We also conducted pooled sequencing of 10 schizophrenic patients and matched controls. Differentially expressed genes were identified by t-test. In the individually sequenced dataset, we identified 198 genes differentially expressed between cases and controls, of them 19 had been verified by the pooled sequencing dataset and 21 reached nominal significance in gene-based association analyses of a genome wide association dataset. Pathway analysis of these differentially expressed genes revealed that they were highly enriched in the immune related pathways. Two genes, S100A8 and TYROBP, had consistent changes in expression in both individual and pooled sequencing datasets and were nominally significant in gene-based association analysis. CONCLUSIONS Integration of gene expression and pathway analyses with genome-wide association may be an efficient approach to identify risk genes for schizophrenia.
Collapse
Affiliation(s)
- Junzhe Xu
- Department of psychiatry, School of Medicine, University at Buffalo, SUNY, Buffalo, NY 14260, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
130
|
The emerging role of Interleukin 27 in inflammatory arthritis and bone destruction. Cytokine Growth Factor Rev 2012; 24:115-21. [PMID: 23165310 DOI: 10.1016/j.cytogfr.2012.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 10/24/2012] [Indexed: 11/24/2022]
Abstract
Although the causes of inflammatory arthritis elude us, aberrant cytokine expression has been linked to joint pathology. Consequently, several approaches in the clinic and/or in clinical trials are targeting cytokines, e.g. tumor necrosis factor (TNF), Interleukin 23 (IL-23) and Interleukin 17 (IL-17), with the goal of antagonizing their respective biologic activity through therapeutic neutralizing antibodies. Such, cytokine signaling-dependent molecular networks orchestrate synovial inflammation on multiple levels including differentiation of myeloid cells to osteoclasts, the central cellular players in arthritis-associated pathologic bone resorption. Hence, understanding of the cellular and molecular mechanisms elicited by synovial cytokine networks that dictate recruitment, differentiation and activation of osteoclast precursors and osteoclasts, respectively, is central to shaping novel therapeutic options for inflammatory arthritis patients. In this article we are discussing the complex signaling interactions involved in the regulation of inflammatory arthritis and it's associated bone loss with a focus on Interleukin 27 (IL-27). The present review will discuss the primary bone-degrading cell, the osteoclast, and on how IL-27, directly or indirectly, modulates osteoclast activity in autoimmune-driven inflammatory joint diseases.
Collapse
|
131
|
Kang S, Kumanogoh A. Semaphorins in bone development, homeostasis, and disease. Semin Cell Dev Biol 2012; 24:163-71. [PMID: 23022498 DOI: 10.1016/j.semcdb.2012.09.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 09/18/2012] [Accepted: 09/19/2012] [Indexed: 01/25/2023]
Abstract
Semaphorins were originally identified as axon guidance cues in the development of the nervous system. In recent years, numerous studies have determined that they are also involved in organogenesis, vascularization/angiogenesis, oncogenesis, and immune responses. In addition, the mechanisms underlying the diverse functions of semaphorins and their receptors have been identified. Recently, significant advances have been made in our understanding of the roles of semaphorins in bone remodeling, particularly the regulation of osteoclast and osteoblast differentiation and migration. Moreover, dysregulated semaphorin expression causes severe bone diseases, including osteoporosis and osteopetrosis. This review focuses on advanced findings on the role of semaphorins/receptors and their intracellular signaling in the regulation of bone homeostasis.
Collapse
Affiliation(s)
- Sujin Kang
- Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Osaka University Graduate School of Medicine, Osaka, Japan
| | | |
Collapse
|
132
|
Abstract
Solid tumors not only comprise malignant cells but also other nonmalignant cell types, forming a unique microenvironment that can strongly influence the behavior of tumor cells. Recent advances in the understanding of cancer biology have highlighted the functional role of semaphorins. In fact, semaphorins form a family of molecular signals known to guide and control cell migration during embryo development and in adults. Tumor cells express semaphorins as well as their receptors, plexins and neuropilins. It has been shown that semaphorin signaling can regulate tumor cell behavior. Moreover, semaphorins are important regulators of tumor angiogenesis. Conversely, very little is known about the functional relevance of semaphorin signals for tumor-infiltrating stromal cells, such as leukocytes. In this chapter, we review the current knowledge on the functional role of semaphorins in cancer progression, and we focus on the emerging role of semaphorins in mediating the cross talk between tumor cells and different tumor stromal cells.
Collapse
Affiliation(s)
- Claudia Muratori
- University of Torino Medical School, Institute for Cancer Research (IRCC), Candiolo, Turin, Italy
| | | |
Collapse
|
133
|
Greter M, Merad M. Regulation of microglia development and homeostasis. Glia 2012; 61:121-7. [PMID: 22927325 DOI: 10.1002/glia.22408] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/25/2012] [Accepted: 07/25/2012] [Indexed: 12/23/2022]
Abstract
Microglia represent the resident macrophages of the central nervous system (CNS) and account for 10% of the adult glial cell population in the normal brain. Although microglial cells are thought to contribute to most pathological conditions including CNS infections, neuroinflammatory lesions, brain tumors, and neurodegenerative diseases, their exact role in CNS development, homeostasis, and disease remains poorly understood. In contrast to most macrophage populations, microglia survive high-dose ionizing radiation and maintain themselves locally and independently of circulating precursors in the steady state. However, controversies remain on the origin of microglia in the brain and whether they could potentially be repopulated by circulating myeloid precursors after brain injury. Microglia-targeted therapies through the use of genetically modified circulating hematopoietic cells proved to be a promising therapeutic strategy for the treatment of brain diseases. It is thus of great importance to understand the contribution and developmental cues of circulating myeloid cells as potential microglia progenitors to the adult pool of microglia in the steady state and under inflammatory conditions.
Collapse
Affiliation(s)
- Melanie Greter
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland.
| | | |
Collapse
|
134
|
Polyethylene particles stimulate expression of ITAM-related molecules in peri-implant tissues and when stimulating osteoclastogenesis in vitro. Acta Biomater 2012; 8:3104-12. [PMID: 22554886 DOI: 10.1016/j.actbio.2012.04.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/05/2012] [Accepted: 04/24/2012] [Indexed: 12/28/2022]
Abstract
Wear particle-induced orthopaedic prosthesis loosening is associated with elevated osteoclast activity. The immunoreceptor tyrosine-based activation motif (ITAM)-related molecules OSCAR, FcRγ, TREM2 and DAP12 are important for osteoclast formation. The aim of this study was to determine if these molecules are involved in peri-implant loosening by investigating their expression in peri-implant tissues obtained at revision of joint replacement components containing polyethylene (PE) wear particles, and in osteoclasts formed in vitro in the presence of PE particles. The results showed that there was a marked and statistically significant increase in protein levels of the ITAM-related molecules in the revision tissues. The levels of OSCAR, FcRγ, TREM2 and DAP12 mRNA in the revision tissues were also increased. In vitro PE particles stimulated osteoclast resorption in the presence of 50 ng ml(-1) receptor activator NFκB (RANKL) and significantly elevated the expression of OSCAR, FcRγ, TREM2 and DAP12 during osteoclast formation. These findings suggest that the ITAM signalling molecules and their co-receptors have a role in pathogenic bone loss associated with implant PE wear.
Collapse
|
135
|
Hayashi M, Nakashima T, Taniguchi M, Kodama T, Kumanogoh A, Takayanagi H. Osteoprotection by semaphorin 3A. Nature 2012; 485:69-74. [PMID: 22522930 DOI: 10.1038/nature11000] [Citation(s) in RCA: 432] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 02/27/2012] [Indexed: 12/27/2022]
Abstract
The bony skeleton is maintained by local factors that regulate bone-forming osteoblasts and bone-resorbing osteoclasts, in addition to hormonal activity. Osteoprotegerin protects bone by inhibiting osteoclastic bone resorption, but no factor has yet been identified as a local determinant of bone mass that regulates both osteoclasts and osteoblasts. Here we show that semaphorin 3A (Sema3A) exerts an osteoprotective effect by both suppressing osteoclastic bone resorption and increasing osteoblastic bone formation. The binding of Sema3A to neuropilin-1 (Nrp1) inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation by inhibiting the immunoreceptor tyrosine-based activation motif (ITAM) and RhoA signalling pathways. In addition, Sema3A and Nrp1 binding stimulated osteoblast and inhibited adipocyte differentiation through the canonical Wnt/β-catenin signalling pathway. The osteopenic phenotype in Sema3a−/− mice was recapitulated by mice in which the Sema3A-binding site of Nrp1 had been genetically disrupted. Intravenous Sema3A administration in mice increased bone volume and expedited bone regeneration. Thus, Sema3A is a promising new therapeutic agent in bone and joint diseases.
Collapse
Affiliation(s)
- Mikihito Hayashi
- Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549, Japan
| | | | | | | | | | | |
Collapse
|
136
|
Bostanci N, Belibasakis GN. Doxycycline inhibits TREM-1 induction by Porphyromonas gingivalis. ACTA ACUST UNITED AC 2012; 66:37-44. [DOI: 10.1111/j.1574-695x.2012.00982.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/12/2012] [Accepted: 04/25/2012] [Indexed: 12/15/2022]
Affiliation(s)
- Nagihan Bostanci
- Oral Translational Research; Institute of Oral Biology; Center of Dental Medicine; University of Zürich; Zürich; Switzerland
| | - Georgios N. Belibasakis
- Oral Microbiology and Immunology; Institute of Oral Biology; Center of Dental Medicine; University of Zürich; Zürich; Switzerland
| |
Collapse
|
137
|
Ishida-Kitagawa N, Tanaka K, Bao X, Kimura T, Miura T, Kitaoka Y, Hayashi K, Sato M, Maruoka M, Ogawa T, Miyoshi J, Takeya T. Siglec-15 protein regulates formation of functional osteoclasts in concert with DNAX-activating protein of 12 kDa (DAP12). J Biol Chem 2012; 287:17493-17502. [PMID: 22451653 DOI: 10.1074/jbc.m111.324194] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Osteoclasts are multinucleated giant cells that reside in osseous tissues and resorb bone. Signaling mediated by receptor activator of nuclear factor (NF)-κB (RANK) and its ligand leads to the nuclear factor of activated T cells 2/c1 (NFAT2 or NFATc1) expression, a critical step in the formation of functional osteoclasts. In addition, adaptor proteins harboring immunoreceptor tyrosine-based activation motifs, such as DNAX-activating protein of 12 kDa (DAP12), play essential roles. In this study, we identified the gene encoding the lectin Siglec-15 as NFAT2-inducible, and we found that the protein product links RANK ligand-RANK-NFAT2 and DAP12 signaling in mouse osteoclasts. Both the recognition of sialylated glycans by the Siglec-15 V-set domain and the association with DAP12 through its Lys-272 are essential for its function. When Siglec-15 expression was knocked down, fewer multinucleated cells developed, and those that did were morphologically contracted with disordered actin-ring structures. These changes were accompanied by significantly reduced bone resorption. Siglec-15 formed complexes with Syk through DAP12 in response to vitronectin. Furthermore, chimeric molecules consisting of the extracellular and transmembrane regions of Siglec-15 with a K272A mutation and the cytoplasmic region of DAP12 significantly restored bone resorption in cells with knocked down Siglec-15 expression. Together, these results suggested that the Siglec-15-DAP12-Syk-signaling cascade plays a critical role in functional osteoclast formation.
Collapse
Affiliation(s)
- Norihiro Ishida-Kitagawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192.
| | - Kunitaro Tanaka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Xilinqiqige Bao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Takanori Kimura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Tadashi Miura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Yoshiki Kitaoka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Kouhei Hayashi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Mizuho Sato
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192; Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871
| | - Masahiro Maruoka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192; Laboratory of Single-Molecule Cell Biology, Tohoku University Graduate School of Life Sciences, Aoba-ku, Sendai, Miyagi 980-8578
| | - Takuya Ogawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| | - Jun Miyoshi
- Department of Molecular Biology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
| | - Tatsuo Takeya
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192
| |
Collapse
|
138
|
Diverse roles for semaphorin−plexin signaling in the immune system. Trends Immunol 2012; 33:127-35. [DOI: 10.1016/j.it.2012.01.008] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/27/2011] [Accepted: 01/11/2012] [Indexed: 12/23/2022]
|
139
|
Otero K, Shinohara M, Zhao H, Cella M, Gilfillan S, Colucci A, Faccio R, Ross FP, Teitelbaum SL, Takayanagi H, Colonna M. TREM2 and β-catenin regulate bone homeostasis by controlling the rate of osteoclastogenesis. THE JOURNAL OF IMMUNOLOGY 2012; 188:2612-21. [PMID: 22312126 DOI: 10.4049/jimmunol.1102836] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
TREM2 is an immunoreceptor expressed on osteoclasts (OC) and microglia that transmits intracellular signals through the adaptor DAP12. Individuals with genetic mutations inactivating TREM2 or DAP12 develop the Nasu-Hakola disease (NHD) with cystic-like lesions of the bone and brain demyelination that lead to fractures and presenile dementia. The mechanisms of this disease are poorly understood. In this study, we report that TREM2-deficient mice have an osteopenic phenotype reminiscent of NHD. In vitro, lack of TREM2 impairs proliferation and β-catenin activation in osteoclast precursors (OcP) in response to M-CSF. This defect results in accelerated differentiation of OcP into mature OC. Corroborating the importance of a balanced proliferation and differentiation of OcP for bone homeostasis, we show that conditional deletion of β-catenin in OcP also results in reduced OcP proliferation and accelerated osteoclastogenesis in vitro as well as osteopenia in vivo. These results reveal that TREM2 regulates the rate of osteoclastogenesis and provide a mechanism for the bone pathology in NHD.
Collapse
Affiliation(s)
- Karel Otero
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
140
|
Ito H, Hamerman JA. TREM-2, triggering receptor expressed on myeloid cell-2, negatively regulates TLR responses in dendritic cells. Eur J Immunol 2012; 42:176-85. [PMID: 21956652 PMCID: PMC3444819 DOI: 10.1002/eji.201141679] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 09/09/2011] [Accepted: 09/20/2011] [Indexed: 01/24/2023]
Abstract
DCs play a key role in defense against infections and also in preventing inflammatory and autoimmune diseases. The response of DCs to pathogens is tightly regulated by many mechanisms to allow for appropriate, but not pathogenic, responses. We previously showed that DCs with deficiencies for two ITAM-bearing signaling adapters, DAP12 and FcRγ, produce more inflammatory cytokines upon treatment with Toll-like receptor (TLR) agonists than WT DCs. Here, we investigated whether the TREM-2 receptor pairs with DAP12 to inhibit TLR responses in DCs. TREM-2-deficient BMDCs showed increased inflammatory cytokine and type I IFN production in response to TLR ligation. Additionally, TREM-2-deficient BMDCs had increased TLR-induced maturation and were more efficient at inducing antigen-specific T-cell proliferation upon CpG DNA stimulation compared with WT BMDCs. Finally, we showed that a TREM-2 ligand is expressed on the surface of BMDCs, suggesting that the TREM-2 receptor transduces inhibitory signals due to recognition of an endogenous ligand.
Collapse
Affiliation(s)
- Hiroaki Ito
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | | |
Collapse
|
141
|
Hada N, Okayasu M, Ito J, Nakayachi M, Hayashida C, Kaneda T, Uchida N, Muramatsu T, Koike C, Masuhara M, Sato T, Hakeda Y. Receptor activator of NF-κB ligand-dependent expression of caveolin-1 in osteoclast precursors, and high dependency of osteoclastogenesis on exogenous lipoprotein. Bone 2012; 50:226-36. [PMID: 22075210 DOI: 10.1016/j.bone.2011.10.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 10/22/2011] [Accepted: 10/25/2011] [Indexed: 02/07/2023]
Abstract
Although extensive studies have done much to clarify the molecular mechanisms of osteoclastogenesis during the last ten years, there may still be unknown molecules associated with osteoclast differentiation. Thus, we used fluorescent differential display to screen for genes whose expression is induced by receptor activator of NF-κB ligand (RANKL), a crucial molecule for osteoclast formation. We identified caveolin-1 (Cav-1) as a RANKL-induced gene. Cav-1 is a major structural protein of caveolae and lipid rafts, cholesterol-enriched microdomains in the plasma membrane (PM). The RANKL-induced Cav-1 was immediately conveyed to lipid rafts. Conversely, expression of flotillin-1 (Flot-1), another scaffolding protein of lipid rafts, was reduced during osteoclastogenesis, indicating conversion of Flot-1-predominant rafts into Cav-1-enriched rafts. However, in vitro osteoclastogenesis of precursor cells from Cav-1-null mice was comparable to that of wild-type mice, while Cav-2 expression in the knockout osteoclasts was maintained. Conversely, Cav-2 gene silencing in Cav-1-null osteoclast precursors using siRNA for Cav-2 increased osteoclast formation, suggesting that the Cav-1/Cav-2 complex may act as a negative regulator for osteoclastogenesis. On the other hand, destruction of lipid rafts by removal of cholesterol from the PM by methyl-ß-cyclodextrin (MCD) treatment caused disordered signal transductions for osteoclastogenesis, such as hyperactivation of Erk1/2 and insensitivity of Akt to RANKL stimulus. The abnormal signaling was reproduced by deleting exogenous lipoproteins from the culture medium, which also resulted in reduced osteoclast formation. In addition, the deletion caused delayed expression of nuclear factor of activated T cells c1 (NFATc1), and depressed its activation in the cytosol and inhibited its translocation into nuclei. Simultaneously, the deletion reduced the level of FcRγ, a trigger protein for initiating the calcium signaling needed to activate NFATc1, and decreased Cav-1 in lipid rafts. These findings indicate that the molecular mechanisms of osteoclastogenesis are highly dependent on extracellular lipoprotein and the integrity of lipid rafts, and suggest possible involvement of cholesterol.
Collapse
Affiliation(s)
- Naoto Hada
- Division of Oral Anatomy, Department of Human Development and Fostering, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
142
|
Kertész Z, Győri D, Körmendi S, Fekete T, Kis-Tóth K, Jakus Z, Schett G, Rajnavölgyi É, Dobó-Nagy C, Mócsai A. Phospholipase Cγ2 is required for basal but not oestrogen deficiency-induced bone resorption. Eur J Clin Invest 2012; 42:49-60. [PMID: 21749368 PMCID: PMC3266491 DOI: 10.1111/j.1365-2362.2011.02556.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 05/16/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND Osteoclasts play a critical role in bone resorption under basal conditions, but they also contribute to pathological bone loss during diseases including postmenopausal osteoporosis. Phospholipase Cγ2 (PLCγ2) is an important signalling molecule in diverse haematopoietic lineages. Here, we tested the role of PLCγ2 in basal and ovariectomy-induced bone resorption, as well as in in vitro osteoclast cultures using PLCγ2-deficient (PLCγ2(-/-) ) mice. MATERIALS AND METHODS The trabecular architecture of long bone metaphyses was tested by micro-CT and histomorphometric analyses. Postmenopausal osteoporosis was modelled by surgical ovariectomy. Osteoclast development and function, gene expression and PLCγ2 phosphorylation were tested on in vitro osteoclast and macrophage cultures. RESULTS PLCγ2(-/-) mice had significantly higher trabecular bone mass under basal conditions than wild-type mice. PLCγ2 was required for in vitro development and resorptive function of osteoclasts, but not for upregulation of osteoclast-specific gene expression. PLCγ2 was phosphorylated in a Src-family-dependent manner upon macrophage adhesion but not upon stimulation by M-CSF or RANKL. Surprisingly, ovariectomy-induced bone resorption in PLCγ2(-/-) mice was similar to, or even more robust than, that in wild-type animals. CONCLUSIONS Our results indicate that PLCγ2 participates in bone resorption under basal conditions, likely because of its role in adhesion receptor signalling during osteoclast development. In contrast, PLCγ2 does not appear to play a major role in ovariectomy-induced bone loss. These results suggest that basal and oestrogen deficiency-induced bone resorption utilizes different signalling pathways and that PLCγ2 may not be a suitable therapeutic target in postmenopausal osteoporosis.
Collapse
Affiliation(s)
- Zsuzsanna Kertész
- Department of Physiology, Semmelweis University School of MedicineBudapest, Hungary
| | - Dávid Győri
- Department of Physiology, Semmelweis University School of MedicineBudapest, Hungary
| | - Szandra Körmendi
- Independent Section of Radiology, Semmelweis UniversityBudapest, Hungary
| | - Tünde Fekete
- Department of Immunology, Medical and Health Science Center, University of DebrecenDebrecen, Hungary
| | - Katalin Kis-Tóth
- Department of Immunology, Medical and Health Science Center, University of DebrecenDebrecen, Hungary
| | - Zoltán Jakus
- Department of Physiology, Semmelweis University School of MedicineBudapest, Hungary
| | - Georg Schett
- Department of Internal Medicine 3, University of Erlangen-NurembergErlangen, Germany
| | - Éva Rajnavölgyi
- Department of Immunology, Medical and Health Science Center, University of DebrecenDebrecen, Hungary
| | - Csaba Dobó-Nagy
- Independent Section of Radiology, Semmelweis UniversityBudapest, Hungary
| | - Attila Mócsai
- Department of Physiology, Semmelweis University School of MedicineBudapest, Hungary
| |
Collapse
|
143
|
Gene expression profile of THP-1 monocytes following knockdown of DAP12, a causative gene for Nasu-Hakola disease. Cell Mol Neurobiol 2011; 32:337-43. [PMID: 22080356 DOI: 10.1007/s10571-011-9769-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 11/01/2011] [Indexed: 01/15/2023]
Abstract
Nasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, is a rare autosomal recessive disorder characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor complex expressed on osteoclasts, dendritic cells, macrophages, monocytes, and microglia. At present, the precise molecular mechanisms underlying development of leukoencephalopathy and bone cysts in NHD remain largely unknown. We established THP-1 human monocyte clones that stably express small interfering RNA targeting DAP12 for serving as a cellular model of NHD. Genome-wide transcriptome analysis identified a set of 22 genes consistently downregulated in DAP12 knockdown cells. They constituted the molecular network closely related to the network defined by cell-to-cell signaling and interaction, hematological system development and function, and inflammatory response, where NF-κB acts as a central regulator. These results suggest that a molecular defect of DAP12 in human monocytes deregulates the gene network pivotal for maintenance of myeloid cell function in NHD.
Collapse
|
144
|
Perälä N, Sariola H, Immonen T. More than nervous: the emerging roles of plexins. Differentiation 2011; 83:77-91. [PMID: 22099179 DOI: 10.1016/j.diff.2011.08.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/27/2011] [Accepted: 08/04/2011] [Indexed: 12/30/2022]
Abstract
Plexins are the receptors for semaphorins, a large family of axon guidance cues. Accordingly, the role of plexins in the development of the nervous system was the first to be acknowledged. However, the expression of plexins is not restricted to neuronal cells, and recent research has been increasingly focused on the roles of plexin-semaphorin signalling outside of the nervous system. During embryogenesis, plexins regulate the development of many organs, including the cardiovascular system, skeleton and kidney. They have also been shown to be involved in immune system functions and tumour progression. Analyses of the plexin signalling in different tissues and cell types have provided new insight to the versatility of plexin interactions with semaphorins and other cell-surface receptors. In this review we try to summarise the current understanding of the roles of plexins in non-neural development and immunity.
Collapse
Affiliation(s)
- Nina Perälä
- Institute of Biomedicine/Biochemistry and Developmental Biology, Biomedicum Helsinki, University of Helsinki, Finland
| | | | | |
Collapse
|
145
|
Satoh JI, Tabunoki H, Ishida T, Yagishita S, Jinnai K, Futamura N, Kobayashi M, Toyoshima I, Yoshioka T, Enomoto K, Arai N, Saito Y, Arima K. Phosphorylated Syk expression is enhanced in Nasu-Hakola disease brains. Neuropathology 2011; 32:149-57. [PMID: 21981270 DOI: 10.1111/j.1440-1789.2011.01256.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DNAX-activation protein 12 (DAP12) or triggering receptor expressed on myeloid cells 2 (TREM2). TREM2 and DAP12 constitute a receptor/adaptor complex on myeloid cells. The post-receptor signals are transmitted via rapid phosphorylation of the immunoreceptor tyrosine-based activating motif (ITAM) of DAP12, mediated by Src protein tyrosine kinases, followed by binding of phosphorylated ITAM to Src homology 2 (SH2) domains of spleen tyrosine kinase (Syk), resulting in autophosphorylation of the activation loop of Syk. To elucidate the molecular mechanism underlying the pathogenesis of NHD, we investigated Syk expression and activation in the frontal cortex and the hippocampus of three NHD and eight control brains by immunohistochemistry. In NHD brains, the majority of neurons expressed intense immunoreactivities for Syk and Y525/Y526-phosphorylated Syk (pSyk) chiefly located in the cytoplasm, while more limited populations of neurons expressed Src. The levels of pSyk expression were elevated significantly in NHD brains compared with control brains. In both NHD and control brains, substantial populations of microglia and macrophages expressed pSyk, while the great majority of reactive astrocytes and myelinating oligodendrocytes did not express pSyk, Syk or Src. These observations indicate that neuronal expression of pSyk was greatly enhanced in the cerebral cortex and the hippocampus of NHD brains, possibly via non-TREM2/DAP12 signaling pathways involved in Syk activation.
Collapse
Affiliation(s)
- Jun-Ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University Department of Clinical Neuropathology, Tokyo, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
146
|
Yoshida K, Higuchi C, Nakura A, Yoshikawa H. Spleen tyrosine kinase suppresses osteoblastic differentiation through MAPK and PKCα. Biochem Biophys Res Commun 2011; 411:774-9. [DOI: 10.1016/j.bbrc.2011.07.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 11/25/2022]
|
147
|
Molecular and cellular mechanisms of mammalian cell fusion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 713:33-64. [PMID: 21432013 DOI: 10.1007/978-94-007-0763-4_4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The fusion of one cell with another occurs in development, injury and disease. Despite the diversity of fusion events, five steps in sequence appear common. These steps include programming fusion-competent status, chemotaxis, membrane adhesion, membrane fusion, and post-fusion resetting. Recent advances in the field start to reveal the molecules involved in each step. This review focuses on some key molecules and cellular events of cell fusion in mammals. Increasing evidence demonstrates that membrane lipid rafts, adhesion proteins and actin rearrangement are critical in the final step of membrane fusion. Here we propose a new model for the formation and expansion of membrane fusion pores based on recent observations on myotube formation. In this model, membrane lipid rafts first recruit adhesion molecules and align with opposing membranes, with the help of a cortical actin "wall" as a rigid supportive platform. Second, the membrane adhesion proteins interact with each other and trigger actin rearrangement, which leads to rapid dispersion of lipid rafts and flow of a highly fluidic phospholipid bilayer into the site. Finally, the opposing phospholipid bilayers are then pushed into direct contact leading to the formation of fusion pores by the force generated through actin polymerization. The actin polymerization generated force also drives the expansion of the fusion pores. However, several key questions about the process of cell fusion still remain to be explored. The understanding of the mechanisms of cell fusion may provide new opportunities in correcting development disorders or regenerating damaged tissues by inhibiting or promoting molecular events associated with fusion.
Collapse
|
148
|
Nakano-Yokomizo T, Tahara-Hanaoka S, Nakahashi-Oda C, Nabekura T, Tchao NK, Kadosaki M, Totsuka N, Kurita N, Nakamagoe K, Tamaoka A, Takai T, Yasui T, Kikutani H, Honda SI, Shibuya K, Lanier LL, Shibuya A. The immunoreceptor adapter protein DAP12 suppresses B lymphocyte-driven adaptive immune responses. ACTA ACUST UNITED AC 2011; 208:1661-71. [PMID: 21727189 PMCID: PMC3149228 DOI: 10.1084/jem.20101623] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
DAP12, an immunoreceptor tyrosine-based activation motif-bearing adapter protein, is involved in innate immunity mediated by natural killer cells and myeloid cells. We show that DAP12-deficient mouse B cells and B cells from a patient with Nasu-Hakola disease, a recessive genetic disorder resulting from loss of DAP12, showed enhanced proliferation after stimulation with anti-IgM or CpG. Myeloid-associated immunoglobulin-like receptor (MAIR) II (Cd300d) is a DAP12-associated immune receptor. Like DAP12-deficient B cells, MAIR-II-deficient B cells were hyperresponsive. Expression of a chimeric receptor composed of the MAIR-II extracellular domain directly coupled to DAP12 into the DAP12-deficient or MAIR-II-deficient B cells suppressed B cell receptor (BCR)-mediated proliferation. The chimeric MAIR-II-DAP12 receptor recruited the SH2 domain-containing protein tyrosine phosphatase 1 (SHP-1) after BCR stimulation. DAP12-deficient mice showed elevated serum antibodies against self-antigens and enhanced humoral immune responses against T cell-dependent and T cell-independent antigens. Thus, DAP12-coupled MAIR-II negatively regulates B cell-mediated adaptive immune responses.
Collapse
Affiliation(s)
- Takako Nakano-Yokomizo
- Department of Immunology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305-8575, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
149
|
Okuno T, Nakatsuji Y, Kumanogoh A. The role of immune semaphorins in multiple sclerosis. FEBS Lett 2011; 585:3829-35. [DOI: 10.1016/j.febslet.2011.03.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 10/18/2022]
|
150
|
Hatterer E, Benon A, Chounlamountri N, Watrin C, Angibaud J, Jouanneau E, Boudin H, Honnorat J, Pellier-Monnin V, Noraz N. Syk kinase is phosphorylated in specific areas of the developing nervous system. Neurosci Res 2011; 70:172-82. [PMID: 21354221 DOI: 10.1016/j.neures.2011.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 01/31/2011] [Accepted: 02/16/2011] [Indexed: 11/26/2022]
Abstract
An increasing number of data involve immunoreceptors in brain development, synaptic plasticity and behavior. However it has yet to be determined whether these proteins in fact transmit an immunoreceptor-like signal in non-hematopoietic neuronal cells. The recruitment and activation of the Syk family tyrosine kinases, Syk and ZAP-70, being a critical step in this process, we conducted a thorough analysis of Syk/ZAP-70 expression pattern in nervous tissues. Syk/ZAP-70 is present in neurons of different structures including the cerebellum, the hippocampus, the visual system and the olfactory system. During the olfactory system ontogeny the protein is detected from the 16th embryonic day and persists in adulthood. Importantly, Syk was phosphorylated on tyrosine residues representative of an active form of the kinase in specialized neuronal subpopulations comprising rostral migratory stream neuronal progenitor cells, hippocampal pyramidal cells, retinal ganglion cells and cerebellar granular cells. Phospho-Syk staining was also observed in synapse-rich regions such as the olfactory bulb glomeruli and the retina inner plexiform layer. Furthermore, our work on cultured primary hippoccampal neurons indicates that as for hematopoietic cells, Syk phosphorylation is readily induced upon pervanadate treatment. Therefore, Syk appears to be a serious candidate in connecting immunoreceptors to downstream adaptor/effector molecules in neurons.
Collapse
Affiliation(s)
- Eric Hatterer
- INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center, Neuro-oncology & Neuro-inflammation Team, University of Lyon 1, Lyon F-69000, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|